A Symmetry‐Broken Charge‐Separated State in the Marcus Inverted Region

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(12)

Published: Jan. 26, 2023

We report a long-lived charge-separated state in chromophoric pair (DC-PDI2 ) that uniquely integrates the advantages of fundamental processes photosynthetic reaction centers: i) Symmetry-breaking charge-separation (SB-CS) and ii) Marcus-inverted-region dependence. The near-orthogonal bichromophoric DC-PDI2 manifests an ultrafast evolution SB-CS with time constant τSB-CS${{\tau }_{{\rm S}{\rm B}-{\rm C}{\rm S}}}$ =0.35±0.02 ps slow charge recombination (CR) kinetics τCR${{\tau R}}}$ =4.09±0.01 ns ACN. rate CR is 11 686 times slower than ACN, as PDI radical ion-pair occurs deep inverted region Marcus parabola ( -ΔGCR${{-{\rm \Delta }G}_{{\rm >λ). In contrast, analogous benzyloxy (BnO)-substituted DC-BPDI2 showcases ≈10-fold accelerated τCR/τSB-CS${{\tau R}}/{\tau lowering to ≈1536 by virtue decreased driving force. present investigation demonstrates control molecular engineering tune energetics material, which essential for next-generation optoelectronic devices.

Language: Английский

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Competitive Charge Separation Pathways in a Flexible Molecular Folda-Dimer

The Journal of Physical Chemistry B, Journal Year: 2024, Volume and Issue: 128(7), P. 1760 - 1770

Published: Feb. 10, 2024

We report the photophysical properties of a molecular folda-dimer system PDI-AnEt2-PDI, where electron-donating N,N-diethylaniline (AnEt2) moiety bridges two electron-accepting perylene diimide (PDI) chromophores. The conformationally flexible PDI-AnEt2-PDI adopts either an open (two PDIs far apart) or folded within π-stacking distance) conformation, depending on solvent environment. characterized photoinduced charge separation dynamics both and forms in solvents varying polarity. form undergoes to give PDI•–-AnEt2•+-PDI (Bridge electron transfer) independent exhibits photoproducts, yielding PDI•–-AnEt2-PDI•+, latter which is formed via symmetry-breaking (SBCS) between π-stacked PDI Our results further indicate that conformational flexibility leads unexpected excimer formation some conditions. In contrast, no observed form, indicating this geometry preferentially yields SBCS instead. provide insight into how systems can be designed built tune competitive pathways.

Language: Английский

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Ultrafast excited-state dynamics and “three-in-one” phototheranostic properties of a phenanthroline-carbolong photosensitizer

Chemical Science, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

The favorable excited-state dynamics, nonlinear optics, and extraordinary phototheranostic capabilities of conjugated metallaaromatics are attractive topics research. A promising multifunctional photosensitizer, double-phenanthroline-carbolong DPC, was investigated comparatively. It featured strong two-photon absorption (2PA) properties within the near-infrared (NIR) range, with a maximum 2PA cross-section ∼7417 GM at 770 nm in MeOH. Time-dependent density functional theory ultrafast dynamics illustrated that fast charge transfer coupled intersystem crossing to stable triplet state outcompeted radiative decays. "three-in-one" phototherapeutic effect included NIR-wavelength excitation, photodynamic therapy, photothermal therapy as subsequently. significant contribution from intrinsic intramolecular communication along DPC skeleton provided possibility for moderate conversion (η = 36.8%) synergistic (Φ Δ 8.4%). Interestingly, singlet oxygen generation also observed when irradiated excitation wavelengths. In vitro experiments demonstrated phototoxicity 4T1 cancer cells. This work offers insights into carbolong highlights their potential applications fields optics phototheranostics.

Language: Английский

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Tuning Excited-State Charge Transfer Character in Cofacial Core-Substituted Perylenediimide Dimers

The Journal of Physical Chemistry B, Journal Year: 2025, Volume and Issue: unknown

Published: March 25, 2025

Understanding the interplay between excimer formation and symmetry-breaking charge separation is important for optimizing in organic photovoltaic materials. To explore this connection, we synthesized four 1,6,7,12-tetrakis(p-X-phenoxy)perylene-(3,4:9,10)-bisdicarboximide cofacially stacked dimers, where X = MeO, tert-butyl, Br, CF3. Steady-state spectroscopy reveals H-type aggregation all while transient absorption shows relatively small changes their excited-state absorptions. However, time-resolved fluorescence (TRF) that relaxation occurs from an initial Frenkel exciton-dominated state to one which transfer (CT) character contributes. Relaxation lower-lying with CT attributed a combination of structural distribution elicited by varying substituents. This study illustrates how subtle structure can combine influence excited dynamics molecular dimers.

Language: Английский

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Symmetry-breaking photoinduced charge transfer state in a near-IR absorbing meso-linked BODIPY dimer

Physical Chemistry Chemical Physics, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

This TOC represents the Polarity dependent charge separation of BODIPY dimer (3D). The transfer lifetime (1 ps for MeOH and 0.5 DMF) has been confirmed using femtosecond transient absorption spectroscopy.

Language: Английский

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